Wrench



13, 1931- G. w. SCHAEFER 1,819,525

WRENC H Filed Oct. 18 1950 Patented Aug. 18, 1931 PATENT OFFICE GEORGEw. SCHAEFER, F QUINCY, MASSACHUSETTS WRENGH- Application filed October11;,"1930. Seria11No.489,538.

Thisinvention applies to wrenches more particularly of the typecomprising a shank integral with one of more heads having openings offixed size for the accommodation of nuts. In accordance with the presentinvention, the head of such a wrench is provided with a member which maybe engaged thereover to diminish the size of the opening and thus toincrease the useful range of the wrench. Inasmuch as the head .ofsuch awrench usually has a nut-receiving opening defined by parallel oppositeside walls, the member for diminishing the size of the opening may takethe general form of a channel, :so that it may be fitted over thehead,with the inner face of its bridge portion parallel to and bearingagainst a side wall, and with the outer face of its bridge portionparallel to the inner face. By using channel members having bridgeportions of various thicknesses, itwill be seen that a wrench'having anopening of fixed size may be made to accommodate nuts of a varietyofsmaller sizes.

With these and other features and objects in view, the invention willnow be described in conjunction with the accompanying drawings, wherein-;Figure 1- shows in perspective a preferred w'typeof duplex wrenchconstructed to embody the present invention.

Figure 2 is a similar view of apreferred form of channel member to beused for this typeof wrench. o

Figure 3 is a side elevation of the wrench with its heads equipped withchannel members whose bridge portions are of different thicknesses.

Figures 4 and 5- represent sections on the lines 4-4 and 55-of Figures 1and 3,re-

' spectively. I

Figures 6 and 7 represent similar sections through slightly'modifiedforms of construct-ion. Y

Figure 8 represents a fragmentary side ele- I modate nuts of twodifferent sizes.

vation of the wrench of Figure 3,,showing one of its heads inverted.

Referring now in detail to the drawings, as

shown in Figure 1, the wrench, which may be made of steel as usual,comprises a shank 1 having integral therewith a pair of heads 2 ofgenerally circular form. Each head has a nut-receiving opening 3, whichis defined by opposite parallel side walls 4 extending inwardly of thehead, and by an inner wall 5 5 shown rounded off. The openings may be ofdifierent sizes, as indicated, so as to accom- Each head has a thinnerportion 6, beginning with one side edge 16 and terminating with thenearer side wall 4, and with ridges 7 formed on opposite faces of thehead, substantially in line with the side wall as shown. Over thethinner portion 6 of the head may be fitted a channel member, whichpreferably takes 5 the form'shown in Figure 2 and comprises a bridgeportion 8 and flange portions 9. When assembled with a head of thewrench as shown in Figure 3, the inner face 10 of the bridge portion 8liesin contactwith the thinner side wall 4 and the outer face 11 of thebridge portion is parallel to theinner face 10. The

.flanges 9 are finished to engage nicely over the thinner portion 6 andare preferably of a thickness equal to the height of the ridgesj5 7 soas to impart a uniform thickness to the head. The bridge portion 8terminatesadjacent to the inner wall 5 of the head, but the flanges 9continue inwardly of the head beyond the inner terminal. 17 of thebridge portion, with theirinner edges 12 straight and substantially inline with the inner face 10 of the bridge portion, so that they abut theridges 7 of the head. The outer edges 13 of the flanges 9 are preferablyrounded ofi to correspond substantially with the contour of the engagedhead portion 6 in order that the a head may present the appearance ofthe head of a usual wrench form after it has been fitted with thechannel member. The thickness of the bridge portion 8 of the channelmember determines the diminution of the size of the nut-receivingopening 3, so that by providing channel members with bridge portions ofdifferent thicknesses, it is possible to accommodate a variety of sizesof nuts in each head. Each channel member may be used interchangeablywith either head, so that with a given number of channel members 7,having bridge portions of different thicknesses, it is possible toaccommodate with a given duplex wrench having differentsized, nutreceiving openings n 2+2 different sizes of nuts. For instance, with twochannel members having bridge portions of different thicknesses, it ispossible to accommodate six different sizes of nuts, and with threechannel members having bridge portions of different thicknesses, eightdifferent sizes of nuts.

In using the wrench, it is preferable to bring the pressure of turningthe nut to bear on the outer face of the bridge portion of the channelmember, for the reason that the tendency is in such case to tighten thechannel member of the head as the pressure is transmitted to andabsorbed by the ridge portions. In other words, when a nut is beingtightened by a clockwise turning movement imparted to the wrench, asindicated by arrow in Figure 3, the ridges 7 are brought to bear againstthe flange edges 12 of the channel member, so that there is no danger ofthe channel member being .forced outwardly of the head, as there wouldbe were the wrench in this position turned anti clockwise so as toseparate the ridges 7 from the flange edges 12 of the channel member.

In order also to use the wrench for loosening nuts to best advantage,that is, with out tendency to causemovement of the channel memberoutwardly of the head, the wrench positioned as shown in Figure 3 shouldbe inverted to the position shown in Figure 8, in which position when anut is being loosened by an anti-clockwise movement imparted-to thewrench, as indicated by arrow, the ridges 7 are again brought to bearagainst the flange edges 12 of the channel member.

When the wrench is used as hereinbefore described, the thin wall 4 ofthe head will take considerable of the stress incident to boththetightening and loosening of nuts. This may cause the wall to spread,especially when the metal is more or less ductile. Inasmuch as suchspreading would impair the nice fit of the flanges 9 of the channelmember over the thin portion 6 of the head, the interior walls of theflanges may be recessed or cutaway at the zones 15 immediately adjacentto the inner face 10 of the bridge portion, as

- ,shown in Figure 7, so as to allow for spreading of the thin wall 4without construction or binding of the channel member. Or, if desired,the thinner portion 6 of the head may be slightly bevelled or taperedtoward its thin wall 4, as illustrated at 14 in Figure 6.

While I have dealt with a preferred embodiment of my invention, it is tobe understood that the principles thereof are applicable to wrenchesother than duplex, and of a form different from that specificallydescribed. For instance, my invention may be applied to a wrench havingonly a single head, in which case, however, the number ofdifferent-sized nuts which can be accommodated by the wrench with agiven number of channel members is reduced in half. A head having a thinportion 6 defined by ridges 7 as described isadvantageous not only inthat the ridges afford a substantial bearing surface for the flangeedges 12 of the channel member, but further in that the strain on theridges is absorbed by the thick body portion of the head, which iscapable of withstanding such strain without danger of fracture.

hat I claim is:

1. The combination with a wrench having a head and a nut-receivingopening in said head defined by parallel opposite side walls extendinginwardly of said head, and a bearing element on said head beyond a sidewall, of a channel member comprising a bridge portion and flangesprojecting therefrom, said bridge portion including an inner face incontact with a side wall and an outer face parallel with said innerface, and said flanges engaging over said head and extending inwardly ofsaid head beyond the inner terminal of said bridge portion to trans mitpressure to said bearing element when a nut is received between saidouter face of said bridge portion and the opposite side wall,and whenthe nut is turned in a direction to apply pressure to said outer face.

2. The combination with a wrench having a flat-faced head and anut-receiving open ing in said head defined by para-llel oposite sidewalls extending inwardly of said head, said head having a thinnerportion beginning with one side edge and terminating with J the nearerside wall and with ridges formed" on opposite faces of said headsubstantially in line wlth said nearer slde wall, of a channel membercomprlsing a bridge portion and ioo flanges projecting therefrom, saidbridge portion including an inner face in contact w1th said nearer sidewall and at an outer face parallel to said inner face, and said flangesengaging over said thinner portion and con- 'tinuing inwardly of saidhead beyond the inner terminal of said bridge portion with their inneredges abutting against said ridges so as to take stress on said ridgeswhen a nut is received between said outer face of said bridge portionand the opposite, side wall and when the nut is turned in a diizorection to apply ressure to said outer face. 3. A member or diminishingthe size of the nut-receiving opening in the head of a Wrench, havingthe general shape of a channel and comprising a bridge portion andflanges projecting therefrom, the inner and outer faces of said bridgeportion being parallel and said flanges being internally recessedimmediately adjacent to the inner face off said bridge portion andcontinuing beyond one of the terminals of said bridge portion Intestimony whereof I have aflixed my signature.

GEORGE W. SCHAEFER.

